1. Technical Field of the Invention
The present invention relates to the new epoxy sulfonamide-based resins. More particularly, the present invention provides a series of novel epoxy sulfonamide resins and a process for their synthesis. The present invention substitutes for aldehydes, e.g., formaldehyde, as presently used in the synthesis of aryl sulfonamide resins, a plurality of non-toxic and environmentally safe epoxy polymers. The epoxy sulfonamide resins of the invention have applications in nail lacquer compositions and other cosmetics, adhesives, and in wood and paper coatings, as a plasticizer and as a modifier in injection molding applications for various resins. Additional applications will be discussed hereinafter.
2. Description of the Prior Art
It is presently known to the art that numerous types of resins may be formed by the condensing of various sulfonamides with aldehydes, such as formaldehyde, furfuraldehyde and acetaldehyde. Aryl sulfonamides condensates have been considered in the literature as super-cooled organic glasses. McMaster, L., J. Am. Chem. Soc. 56, 204 (1934); Walter, G., Trans. Faraday Soc., 32, 406 (1936).
The earliest application of sulfonamides as nitrocellulose plasticizers was disclosed by Schmidt, U.S. Pat. No. 758,335, issued Apr. 26, 1904, wherein such sulfonamides replaced the use of camphor. See, Hyatt, U.S. Pat. No. 105,338.
The use of sulfonamide aldehyde resins in film forming compositions with cellulose esters and esters was, apparently, first taught by H. A. Gardner, U.S. Pat. No. 1,564,664, issued Apr. 7, 1925.
It is, further, generally known in the art that aryl sulfonamides and aryl sulfonamide aldehyde resins are compatible, to varying degrees, with a variety of other types of resins. Depending upon the degree of plasticization, the physical properties of the resins may be so enhanced. Properties of the plasticized resins which may be improved include, flexibility, resistance to water permeability, strength, brilliance, elongation, toughness, adhesion and gloss. Examples of resins whose properties are improved by plasticizing sulfonamides and sulfonamide aldehyde resins includes, e.g., cellulose nitrate, cellulose acetate, ethyl cellulose, nylon, zein, and cellulose acetate butyrate.
The improvement in physical properties is believed to be evident with respect to the properties of films, as well as in injection molded articles. In particular, the toluene sulfonamide formaldehyde-based resins have found a niche in the coatings industry for use as a component in wood finishes, paper coatings, and barrier cating for cellophane. Such resins have also found wide use in coatings which may come into contact with food. One particularly useful and important application of such resins, which has proliferated in recent years, is their use as a component in nail lacquer composition for cosmetics. In this application, superior properties of the sulfonamide resins are evident in the enhanced brilliance, gloss clarity, adhesion, flexibility and resistance-to-water-spotting conferred on the plasticized nitrocellulose film that results.
During the past several years, there has been a growing concern about the use of any type of aldehyde condensate, particularly, formaldehyde condensates, both in the workplace and in the area of consumer products, be it adhesives, coatings, e.g., textile coatings, or in the formulation and application of cosmetics, etc. This growing concern, in part, is attributable to research which has determined that formaldehyde is suspected to be a human carcinogen.
In an effort to replace the use of sulfonamide formaldehyde resins with less toxic substitutes, rosin esters, acrylic resins, polyester resins and certain emulsion type resins have been used. The use of such substitutes, however, has been less than satisfactory in result. Invariably, the finished formulation would have numerous drawbacks in performance characteristics including, but not limited to, adhesion, gloss, water resistance, brilliance and clarity of film.
The "brilliance" exhibited by toluene sulfonamide apparently carries through to resinous products formed by the reaction of toluene sulfonamide with appropriate reactants which, in the foregoing instances, clearly do not contain any sulfonamides.
It is speculated by the inventor that the clarity and brilliance exhibited by those formulations utilizing sulfonamide-based resins are attributable to the refractive index of the sulfonamides themselves.
The solubility and long-term stability of sulfonamide formaldehyde resins, especially in n-butyl acetate, has always been a very important characteristic for use in nail lacquer formulations. These formulations contain cellulose nitrate and the sulfonamide resins act as plasticizers, conferring desirable properties in the end product.
There is presently a need, thus far unfulfilled, for sulfonamide resins, which exhibit the foregoing beneficial properties, yet do not contain formaldehyde and the inherent drawbacks attendant with its use. Heretofore, the use of formaldehyde has been required as a reactant in the synthesis of sulfonamide resins.